Signaling and telephone system



C. W. KECKLER.

SIGNALING AND TELEPHONE SYSTEM.

APPLICATION FILED MAR.27,1918.

Patented Aug. 9, 1921.

UNITED STATES PATENT G net CHARLES W. KECKLER, OF NEWARK, NEW JERSEY,ASSIGNOR TG WES TERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y.,A GORPORATIQN-QF NEW YORK.

SIGNALING AND rnnnr ionn SYSTEM.

Specification of Letters Patent. Patgnted Aug. 9 1%)21;

Application filed March 27, 1918.

To all whom it may concern:

Be it known that I, CHARLES W. Knox- LER, a citizen of the UnitedStates, residing at Newark, in the county of Essex, State of satingsignaling current, and in accordance with this feature, a plurality ofrelays are associated in such a way as to produce pulsating currentcfroma direct current source for application in a signaling circuit.

Another object is the direct provision of local battery to anyintercommunicating station in connection with a trunk line and inaccordance with this feature one of the relays also serves as animpedance means on establishment of the talking circuit.

Other objects and features of the invention will be apparent from thefollowing specification.

In the drawing, which diagrammatically illustrates one embodiment of thepresent invention, three stations of an intercommunicating system areshown together with a trunk line extending to an exchange; the answeringjack shown to the left of the dotted line being located at thisexchange.

and the apparatus to the right thereof being at the intercommunicatingend of the trunk.

The stations A, B and C of the intercommunicating system shown are ofthe usual type in which connection between stations is obtained bydepression of selective keys such as A, B and C through whichcconnectionwith the line conductors of the station called is made and such stationsignaled. On operation of the signal at any station response is made bydepressing the home key H at such station and removing'the receiver fromthe switchhook in. the usual manner. The depression of the 'home keyconnects the set of the called station to its line conductors and atalking circuit is thus establishedbetween such stations, talking SerialNo. 224,923.

current being supplied from talking battery 10 to each of such stationsthrough impedance coils 11 located thereat.

The intercommunicating keys, with the exception of the home keys H, havethree positions, namely, normal position i as shown on the drawing;way-down or signaling position in which the first and second, and thirdand fourth contacts are engaged and in'which the third contact is alsoengaged with the bus bar 12 connected with ringing battery 13; andintermediate or talking position in which the conditions are the same asfor the signaling position except that there is no engagement with thebus bar 12. The home keys H need only have-a normal and an intermediateposition since it is not necessary that any of the contacts thereofengage the bus bar 12 under any conditions. A locking plate 14 looks anydepressed key in intermediate position until itis released by depressionof another key.- 7 1;

Such stations of the intercommunicating system as it is desired toprovide with trunk service will be equipped with a trunking key Tsimilar to the intercommunicating keys and operable to connect itsstation to the trunk line 15,15 through conductors 16, 16. All threestations are shown as having such trunk connections but obviously itcould be omitted at certain stations without interfering with theoperation: of the intercommunicating system.

In describing the trunking arrangement, the operation which takes placeon an intercommunicating station seeking connection with the exchange atwhich the-answering jack 17 is located will first be outlined;

Assume that station A desiresfsuch a connection. The key T at station Ais depressed to signaling position, thereby engaging the third contactthereof with the bus bar 12 and completing an operating circuit for therelay 18. This circuit extends from one side of battery 13, conductor19,

bus bar '12, third contact of key :T, conductors. 16:, 15 and 20,armature andnormal contact of relay 21, conductor 22, winding of relay18, and conductor 23 to theother sideof battery 13. TherelaylS is accordingly operated, disconnecting thetrunk sig n-al 24 from the trunk, lineand connecting a local battery 25 across the trunk conductors 15,; 15..Current therefrom'flows momentarily over theline conductors 15 andw15and through the winding of the answering signal 26 at the exchange.Another path is also providedthrough one of the windings of the relay 21which, as shown,'has a plurality of windings. This path begins at theupper side of battery 25 and extends over conductor 27 upper armatureand alternate contact of relay 18, conductors 15 and 35, and lowerwinding of relay 21 to the lower side of battery 25. A condenser 28 isprovided in the conductor15' between the connection of the lowerarmature of relay 18 and the conductor 20 and prevents the energizationof the upper winding of relay 21 at this time. Under these conditionsthe armature of relay 21 will be attracted, opening the circuit previously traced for relay 18, which is thereby deenergized and itsarmatures retracted. This interrupts the flow of battery to the signal26 and also opens the energizing circuit for the lower winding ofrelay21. Its armature accordingly returns to normal position, reestablishingthe circuit for relay 18. Operation of relay 18 again supplies batteryto the signal 26 and also actuates the relay 21, as previouslyexplained, to'open the circuit of relay 18. This action is repeated solong as the key T is maintained in signaling position and the pulsatingcurrent thus generatedwill actuate the signal 26 at the exchange,indicating that a party is calling. It is only necessary to retain key Tin signaling position momentarily in order to actuate the signal 26, andthereafter it is permitted to return to intermediate position, and thecalling party removes the receiver 29 from the switchliook 30 tocomplete the talking connection with the trunk line. The key T being outof signaling position, the relay 18 cannot be energized, but on closureof the switchhook 30, a talking circuit is established through the relay21 to supply local battery to the station associated with the trunk.This circuit extends. from upper side of battery 25, conductor 31, upperwinding of relay 21, conductors 20, 15 and 16, third and fourth contactsof key T, conductor 32, switchhook 30, receiver 29, transmitter'33,conductor .34, second and first contacts of key T, conductors 16, 15 and35 and lower winding of relay 21 to the lower side of battery 25. Thewindings of relay 21 accordingly serve as impedance means for talkingcurrent supplied to stations connected with the trunk line while theprovision of the condenser 28 in the trunk conductor 15 prevents directcurrent battery being supplied to the exchange end of the trunk, thoughpermitting the passage of the fluctuating voice currents therethrough totelephonically connect the "intercommunicating sta tions with theexchange.

The operator at the exchange on observing the signal 26 would answer byplugging into the jack 17 and establish connection with the line desiredin the usual manner, talking current being supplied to the exchange endof thetrunk line from the battery of the exchange (not shown) or in anyother desired manner. 7

. On establishment of a talking connection with an outside station theparties would converse in the usual manner, and due to the .fact thatrelay '21 is operated when an inter communicating station obtains atalking connection with the trunk, the depression of the trunk'key T ofother stations to signaling position will not develop signaling current,inasmuch as the circuit of the relay 18 is open at the armature of relay21. Ohviously, were such current generated it would cause annoyancethrough the development of unpleasant noises in the receivers of theparties talking.

at termination of conversation the parties restore their receivers totheir respective switchhooks. The party at station A thereupon depresseskey T to lowermost position, operating relays 18 and 21 as before, andimpressing pulsating signaling current on conductors 15 and 15 tothereby operate the disconnect signals (not shown) at the exchange. Theexchange operator thereupon withdraws the plug (not shown) from the jack17', while the party at station A would open the talking circuit atth'eswitchhook 30, whereupon the relay 21 would be restored to normal. Altersignaling to disconnect the key T at station A would return to and beheld in intermediate position but would not interfere with the operationof the system, inasmuchas the talking circuit thereat would be open atthe switchhook '30. The key TY would, however, be released to normalposition on another key being depressed in obtaining another connection.

In order tov answer calls received through the exchange the trunklinc isshown as provided with a signal 2%,normally bridged across theconductors and operated by sig naling current from the exchange. Thissignal would be located so as to be convenient to at least one of theintercommunicating stations. The station observing the signal wouldremove the receiver 29 from the switchhook 30 and depress trunk key Tthereat to intermediate position, thereupon completing atalkingconnection with the trunk line as previously outlined. The relay 21would be actuated thereby and prevent the momentary application ofsignalingcurrent from battery '25 to the trunk even should the key T bedepressed to signaling position in actuation.

It will be observed that when an intercommunicating station signals theexchange the operation of relay 18 opens the bridging circuit of thesignal 24 during the application of signaling current to the conductors15, 15 so that even should signal 24 be operable on the pulsatingcurrent developed through the cooperation of the relays 18 and 21 itwill not be actuated to the annoyance of the party signaling. Theoperation of relay 18 further prevents the formation of a parallel paththrough the signal 24: for the signaling current generated, so that theanswering signal 26 at the exchange will be sure to receive a sufficientamount of current to operate satisfactorily. The signal 24: al-- thoughbridged across the circuit during talking is preferably of such highimpedance that it will not materially interfere with the transmission.

Vhat is claimed is:

1. A telephone system comprising a line, a signal connected therewith,telephonic apparatus, a source of current, switching means, a relayenergized upon the actuation of said switching means to connect saidsource of current with said line for operating said signal, and a secondrelay operating as a result of the energization of said first relay tocause the deenergization thereof and operating independently of saidfirst relay as a result of the connection of said telephonic apparatuswith said line.

2. A telephone system comprising a line, a signal associated with saidline, a subscribers set for telephonic association with said line, asource of direct current, a relay operable to connect said source ofcurrent with said line, an operating circuit for said relay, a secondrelay operable to open said circuit, an operating circuit for saidsecond relay controlled by operation of said first relay, and anotheroperating circuit for said second relay completed as a result oftelephonic association of said subscribers set with said lineindependent of said first relay.

3. A telephone system comprising a line, a signal associated with saidline, a subscribers set for telephonic association with said line, asource of direct current, arelay operable to connect said source ofcurrent with said line, an operating circuit for said relay, a secondrelay having a plurality of windings and operable to open said circuit,an operating circuit for said second relay including one of saidwindings and controlled by operation of said first relay, and anotheroperating circuit for said relay including another of said windings andcompleted as a result of telephonic association of said subscribers setwith said line independent of said first relay.

4. A telephone system comprising a line, a signal associated with saidline, a subscribers set for telephonic association with said line, asource of direct current, a relay operable to connect said source ofcurrent with said line, an operating circuit for said relay, a secondrelay serving as an impedance means during telephonic association ofsaid set with said line and operable to open said circuit, an operatingcircuit for said second relay controlled by operation of said firstrelay, and another operating circuit for said second relay completed asa result of telephonic association of said set with said line.

5. A telephone system comprising a line, a signal associated with saidline, a subscribers set, means to associate said set with said line, asource of direct current, a relay serving when operated to connect saidsource of current with said line to operate said signal, an operatingcircuit for said relay, a second relay operable to open said circuit, anoperating circuit for said second relay controlled by operation of saidfirst relay, and another operating circuit for said relay completed as aresult of establishment of telephonic association of said set with saidline.

In witness whereof I hereunto subscribe.

my name this 18th day of March, A. D. 1918.

CHARLES W. KECKLER.

